fsci-conformance 0.3.0

#![forbid(unsafe_code)]
//! Live SciPy differential coverage for fsci's
//! `mquantiles(data, prob, alphap, betap)` — plotting-position
//! quantile estimator with configurable (α, β) interpolation.
//!
//! Resolves [frankenscipy-hmaho]. The oracle calls
//! `scipy.stats.mstats.mquantiles(data, prob, alphap=alphap,
//! betap=betap)`.
//!
//! 3 datasets × 4 (α, β) variants (Cunnane, R5, R7, R8) × 4
//! probs (0.05, 0.25, 0.5, 0.95) = 48 cases via subprocess.
//! Each case compares one quantile element-wise. Tol 1e-12 abs
//! (closed-form linear-interpolation chain).
//!
//! Probs were widened back to [0.05, 0.95] after the fix for
//! [frankenscipy-13w1q] landed — fsci now clamps aleph to
//! [1, n-1] before splitting into the interpolation pair,
//! matching scipy's mstats.mquantiles convention.

use std::collections::{BTreeMap, HashMap};
use std::fs;
use std::io::Write;
use std::path::PathBuf;
use std::process::Stdio;
use std::time::{Instant, SystemTime, UNIX_EPOCH};

use fsci_conformance::{ArmCounts, CompareLedger};
use fsci_stats::mquantiles;
use serde::{Deserialize, Serialize};

const PACKET_ID: &str = "FSCI-P2C-007";
const ABS_TOL: f64 = 1.0e-12;
const REQUIRE_SCIPY_ENV: &str = "FSCI_REQUIRE_SCIPY_ORACLE";

#[derive(Debug, Clone, Serialize)]
struct PointCase {
    case_id: String,
    data: Vec<f64>,
    prob: Vec<f64>,
    alphap: f64,
    betap: f64,
}

#[derive(Debug, Clone, Serialize)]
struct OracleQuery {
    points: Vec<PointCase>,
}

#[derive(Debug, Clone, Deserialize)]
struct PointArm {
    case_id: String,
    values: Option<Vec<f64>>,
}

#[derive(Debug, Clone, Deserialize)]
struct OracleResult {
    points: Vec<PointArm>,
}

#[derive(Debug, Clone, Serialize)]
struct CaseDiff {
    case_id: String,
    arm: String,
    abs_diff: f64,
    pass: bool,
}

#[derive(Debug, Clone, Serialize)]
struct DiffLog {
    test_id: String,
    category: String,
    case_count: usize,
    compared: BTreeMap<String, ArmCounts>,
    max_abs_diff: f64,
    pass: bool,
    timestamp_ms: u128,
    duration_ns: u128,
    cases: Vec<CaseDiff>,
}

fn output_dir() -> PathBuf {
    PathBuf::from(env!("CARGO_MANIFEST_DIR")).join(format!("fixtures/artifacts/{PACKET_ID}/diff"))
}

fn ensure_output_dir() {
    fs::create_dir_all(output_dir()).expect("create mquantiles diff output dir");
}

fn timestamp_ms() -> u128 {
    SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .map_or(0, |d| d.as_millis())
}

fn emit_log(log: &DiffLog) {
    ensure_output_dir();
    let path = output_dir().join(format!("{}.json", log.test_id));
    let json = serde_json::to_string_pretty(log).expect("serialize mquantiles diff log");
    fs::write(path, json).expect("write mquantiles diff log");
}

fn generate_query() -> OracleQuery {
    let probs = vec![0.05, 0.25, 0.5, 0.95];
    let datasets: Vec<(&str, Vec<f64>)> = vec![
        ("compact_n12", (1..=12).map(|i| i as f64).collect()),
        (
            "spread_n20",
            (1..=20).map(|i| (i as f64).sqrt() * 4.0).collect(),
        ),
        (
            "ties_n14",
            vec![
                1.0, 2.0, 2.0, 3.0, 3.0, 3.0, 4.0, 4.0, 5.0, 5.0, 5.0, 6.0, 6.0, 7.0,
            ],
        ),
    ];

    // (label, alphap, betap)
    let variants: Vec<(&str, f64, f64)> = vec![
        ("cunnane", 0.4, 0.4),
        ("r5", 0.5, 0.5),
        ("r7", 1.0, 1.0),
        ("r8", 1.0 / 3.0, 1.0 / 3.0),
    ];

    let mut points = Vec::new();
    for (name, data) in &datasets {
        for (label, alphap, betap) in &variants {
            points.push(PointCase {
                case_id: format!("{name}_{label}"),
                data: data.clone(),
                prob: probs.clone(),
                alphap: *alphap,
                betap: *betap,
            });
        }
    }
    OracleQuery { points }
}

fn scipy_oracle_or_skip(query: &OracleQuery) -> Option<OracleResult> {
    let script = r#"
import json
import math
import sys
import numpy as np
from scipy.stats import mstats

def vec_or_none(arr):
    out = []
    for v in arr:
        try:
            v = float(v)
        except Exception:
            return None
        if not math.isfinite(v):
            return None
        out.append(v)
    return out

q = json.load(sys.stdin)
points = []
for case in q["points"]:
    cid = case["case_id"]
    data = np.array(case["data"], dtype=float)
    prob = np.array(case["prob"], dtype=float)
    alphap = float(case["alphap"]); betap = float(case["betap"])
    val = None
    try:
        out = mstats.mquantiles(data, prob=prob, alphap=alphap, betap=betap)
        val = vec_or_none(np.asarray(out).tolist())
    except Exception:
        val = None
    points.append({"case_id": cid, "values": val})
print(json.dumps({"points": points}))
"#;
    let query_json = serde_json::to_string(query).expect("serialize mquantiles query");
    let mut child = match fsci_conformance::scipy_oracle_command()
        .arg("-c")
        .arg(script)
        .stdin(Stdio::piped())
        .stdout(Stdio::piped())
        .stderr(Stdio::piped())
        .spawn()
    {
        Ok(c) => c,
        Err(e) => {
            assert!(
                std::env::var(REQUIRE_SCIPY_ENV).is_err(),
                "failed to spawn python3 for mquantiles oracle: {e}"
            );
            eprintln!("skipping mquantiles oracle: python3 not available ({e})");
            return None;
        }
    };
    {
        let stdin = child.stdin.as_mut().expect("open mquantiles oracle stdin");
        if let Err(err) = stdin.write_all(query_json.as_bytes()) {
            let output = child.wait_with_output().expect("wait for failed oracle");
            let stderr = String::from_utf8_lossy(&output.stderr);
            assert!(
                std::env::var(REQUIRE_SCIPY_ENV).is_err(),
                "mquantiles oracle stdin write failed: {err}; stderr: {stderr}"
            );
            eprintln!("skipping mquantiles oracle: stdin write failed ({err})\n{stderr}");
            return None;
        }
    }
    let output = child
        .wait_with_output()
        .expect("wait for mquantiles oracle");
    if !output.status.success() {
        let stderr = String::from_utf8_lossy(&output.stderr);
        assert!(
            std::env::var(REQUIRE_SCIPY_ENV).is_err(),
            "mquantiles oracle failed: {stderr}"
        );
        eprintln!("skipping mquantiles oracle: scipy not available\n{stderr}");
        return None;
    }
    let stdout = String::from_utf8_lossy(&output.stdout);
    Some(serde_json::from_str(&stdout).expect("parse mquantiles oracle JSON"))
}

#[test]
fn diff_stats_mquantiles() {
    let query = generate_query();
    let Some(oracle) = scipy_oracle_or_skip(&query) else {
        return;
    };
    assert_eq!(oracle.points.len(), query.points.len());

    let pmap: HashMap<String, PointArm> = oracle
        .points
        .into_iter()
        .map(|r| (r.case_id.clone(), r))
        .collect();

    let start = Instant::now();
    let mut diffs = Vec::new();
    let mut max_overall = 0.0_f64;
    let mut ledger = CompareLedger::new("diff_stats_mquantiles", &["mquantiles"]);

    for case in &query.points {
        let scipy_arm = pmap.get(&case.case_id).expect("validated oracle");
        let rust_vec = mquantiles(&case.data, &case.prob, case.alphap, case.betap);
        // slices records a missing oracle, a length mismatch, and a non-finite fsci
        // quantile against a finite SciPy one.
        let Some((scipy_vec, rust_vec)) = ledger.slices(
            "mquantiles",
            &case.case_id,
            scipy_arm.values.as_deref(),
            Some(rust_vec.as_slice()),
        ) else {
            continue;
        };
        let mut case_pass = true;
        for (i, (r, s)) in rust_vec.iter().zip(scipy_vec.iter()).enumerate() {
            // Only a non-finite value slices already matched against SciPy's is skipped.
            if r.is_finite() {
                let abs_diff = (r - s).abs();
                max_overall = max_overall.max(abs_diff);
                case_pass &= abs_diff <= ABS_TOL;
                diffs.push(CaseDiff {
                    case_id: case.case_id.clone(),
                    arm: format!("p{}", case.prob[i]),
                    abs_diff,
                    pass: abs_diff <= ABS_TOL,
                });
            }
        }
        ledger.compared("mquantiles", &case.case_id, case_pass);
    }

    let all_pass = diffs.iter().all(|d| d.pass);

    let log = DiffLog {
        test_id: "diff_stats_mquantiles".into(),
        category: "scipy.stats.mstats.mquantiles (alphap, betap)".into(),
        case_count: diffs.len(),
        compared: ledger.counts().clone(),
        max_abs_diff: max_overall,
        pass: all_pass,
        timestamp_ms: timestamp_ms(),
        duration_ns: start.elapsed().as_nanos(),
        cases: diffs.clone(),
    };

    emit_log(&log);

    for d in &diffs {
        if !d.pass {
            eprintln!(
                "mquantiles mismatch: {} arm={} abs={}",
                d.case_id, d.arm, d.abs_diff
            );
        }
    }

    assert!(
        all_pass,
        "mquantiles conformance failed: {} cases, max_abs={}",
        diffs.len(),
        max_overall
    );
    ledger.finish(query.points.len());
}